The invention relates to a method for the in-vivo non-invasive measurement of a biological parameter of a person employing the placement of current injecting electrodes on the person""s body, and the placement of measurement electrodes on said person""s body between the current injecting electrodes, feeding a measuring current through the current injecting electrodes and the body connected thereto, and measuring a voltage over the measurement electrodes indicative for the biological parameter.
Such a method is known from the article xe2x80x9cOptimalisation of the spot electrode array in impedance cardiography, by Woltjer H H et al, Medical and Biological Engineering and Computing 1996, (34) pages 84-87. In said citation it is proposed to apply an arrangement on the persons body, employing nine spot electrodes of which five are current injecting electrodes and four are voltage pick-up electrodes.
It is the object of the invention to reduce the number of electrodes that are to be used in the measurement method according to the preamble, whilst maintaining the reliability and repeatability of the known method. Obviously reducing the number of electrodes needed in this method is more comfortable for the patient and more practical for medical personnel, especially in the intensive care unit and after extensive surgery.
The object and further advantages of the invention are realised in the method specified in the appended claims.
In a first aspect of the invention a first measurement electrode is placed near a clavicle of the person and a second measurement electrode is placed at the person""s left-hand side below the sternum.
Preferably the first measurement electrode is placed in the triangular clavicular space between the person""s neck and shoulder.
It has been found advantageous that the lowest current injecting electrode is placed at least 6 cm below the second measurement electrode and preferably this lowest current injecting electrode is placed 15-20 cm below the second measurement electrode.